Holding structure of spectacle lens, repair method for the same, and spectacles

ABSTRACT

A method is provided for securely holding a spectacle lens. Without using screwing members such as a screw and a nut, and extra parts such as a bush, a cylindrical pin and a slip-off preventive pin, a spectacle lens can surely be held. A taper pin is provided projecting on a lens holding member for holding a spectacle lens, and a taper hole having approximately the same size as the taper pin is provided on the spectacle lens. The taper pin is directly press-fitted into the taper hole, thereby holding the spectacle lens by a press-contact between an inner circumferential surface of the taper hole and an outer circumferential surface of the taper pin. The taper pin is press-fitted in a thickness direction of the spectacle lens.

This is a Continuation of application Ser. No. 10/537,552, filed Oct.13, 2005, which in turn is a National Phase of PCT/JP04/07376, filed May28, 2004. The disclosures of the prior applications are herebyincorporated by reference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a holding structure of a spectacle lenspreferably applied to spectacles of a rimless type, and a repair methodfor repairing the holding structure of the spectacle lens, and aspectacle frame using the holding structure of the spectacle lens, andspectacles using the holding structure of the spectacle lens.

BACKGROUND ART

In recent years, spectacles of a rimless type attract attention asspectacles having such advantages as to assure the width of visualfields and attain weight reduction. In one of the holding structures ofa spectacle lens of the above-described spectacles of a rimless type, ascrew insertion hole is formed penetrating the spectacle lens, the screwformed on the lens holding member is inserted into the screw insertionhole, and a nut is tightened to the tip of the screw, thereby holdingthe spectacle lens so as to put the spectacle lens between the lensholding member and the nut from the front and rear sides of the lens.(For example, see Patent Document 1 and Patent Document 2).

However, when holding the spectacle lens by means of screwing memberssuch as a screw and a nut, the problem is that the screw becomes looseeasily. Therefore, the spectacle lens holding structure holding thespectacle lens by simply inserting a pin into the hole of the lenswithout using the screw is provided. The present invention relates tothe spectacle lens holding structure designed to hold the spectacle lensby simply inserting the pin into the hole of the lens, without using theabove-described screwing members such as a screw and a nut.

For example, in one of the holding structure of the spectacle lens forholding the spectacle lens by inserting the pin, a taper pin is insertedinto a through hole formed on the spectacle lens through a bush, and bythe inserting action of the taper pin, the bush is made expanded and byproviding a pin slip-off preventive structure separately, the lens isheld (For example, see Patent Document 3).

In another example of the above-described holding structure, acylindrical pin having a slit and formed in the lens holding member isinserted into the through hole provided on the spectacle lens, and aslip-off preventive member is pushed into the cylindrical pin from theopposite side to expand the cylindrical pin by the slip-off preventivemember, thereby bringing the cylindrical pin into press-contact with thehole to hold the lens (For example, see patent document 4).

[Patent document 1] Japanese Utility Model No. 04-63419

[Patent document 2] Japanese Patent Laid-open No. 63-6521

[Patent document 3] PCT Japanese Publication No. 2002-52976

[Patent document 4] Japanese Patent Laid open No. 2000-171758

DISCLOSURE OF THE INVENTION Problem to be Solved

However, in a lens holding structure according to the patent document 3,a taper pin is inserted into a hole on a lens side through a bush,thereby increasing the number of fine parts, and making a through holelarger in diameter by a quantity required for the bush, and thereforethe problem is that the strength of the lens is decreased. In addition,another problem is that since the bush is made of plastic and rubber,the bush may be cut and crushed, or since there is a possibility thatthe bush itself is deteriorated in quality, the lens and the frame maybe shaken and unfastened. In addition, a slip-off preventive structureis separately required.

Further, in the lens holding structure according to the patent document4, since the resin and rubber bush is not used, it is free of theabove-described problems. However, in addition to providing acylindrical pin having a slit on a lens holding member, the slip-offpreventive member pushed into the cylindrical pin from the opposite sidealso needs to be prepared, thereby complicating the structure andincreasing cost.

In view of the above-described circumstances, an object of the presentinvention is to provide a holding structure of a spectacle lens capableof surely holding the spectacle lens with a simple structure, withoutusing screwing members such as a screw and a nut, and extra parts suchas a bush, a cylindrical pin, and a slip-off preventive pin, and arepair method for repairing the holding structure of the spectacle lens,and a spectacle frame applied to the holding structure of the spectaclelens, and spectacles using the holding structure of the spectacle lens.

[Means to be Solved]

A first aspect of the present invention provides a holding structure ofa spectacle lens applied to spectacles of a rimless type in which ataper pin formed in tapered shape having a thin tip end side is providedprojecting on a lens holding member for holding the spectacle lens, ataper hole having a taper of approximately the same size as the taperpins is formed on the spectacle lens, the taper pin is directlypress-fitted into the taper hole, and by bringing the innercircumferential surface of the taper hole into press-contact with theouter circumferential surface of the taper pin, the spectacle lens isheld.

The size of the taper is expressed by the ratio of the difference ofdiameter of both ends to the length of the taper pin, or is defined asan angle (taper angle) formed by a center axis of the taper and agenerating line of the tapered surface. Also, the size of the taper canbe defined as “tan θ ” when the taper angle is set to be θ.

In this case, the spectacle lens made of plastic is usually used becauseit is difficult to be broken by press-fitting the taper pin. Thepress-contact force between the taper pin and the tapered hold isdetermined by a friction coefficient between the pin and the lens, and aforce by which the lens tends to shrink. In the present invention, bythe direct press-contact between the outer circumferential surface ofthe taper pin and the inner circumferential surface of the taper hole, alens holding force can be obtained (without using a bush). Therefore,without shaking and unfastening, the lens can be surely held.

In addition, by directly press-fitting the taper pin into the taperhole, the number of fine parts (such as a bush and a slip-off preventivepin) can be reduced, thereby simplifying the structure and design.Further, by only using a thin taper pin without using the bush andcylindrical pin, the diameter of the hole provided on the spectacle lensside can be made small, thereby preventing the lens strength fromlowering. Accordingly, the above-described lens holding structure can beapplied to a thin lens without developing so much trouble. Moreover, thehole can be made close to the edge of the lens, thereby easily ensuringthe width of effective visual fields. Moreover, the part (attachmentpatch) on the lens holding member side, to which the taper pin isattached, can be made small, thereby enabling easing restriction indesign.

In the holding structure of the spectacle lens of a first aspect of thepresent invention, a direction in which the taper pin is press-fitted isnot limited, including the case where the taper pin is press-fitted intothe taper hole bored in the edge surface of the spectacle lens. However,the holding structure of the spectacle lens of a second aspect of thepresent invention limits the structure in such a way the taper hole isbored in a thickness direction of the lens, and taper pin ispress-fitted thereinto in the thickness direction of the spectacle lens.

As described above, when limiting the structure so that the taper pin ispress-fitted in a thickness direction of the lens, that is, the taperhole is bored in the surface of the lens, and the taper pin ispress-fitted to the taper hole, the following advantage can be obtained.That is, generally, the attachment patch having the taper pin attachedthereto is easy to enter the field of view of a wearer, but according tothe present invention as described above, the diameter of the taper pinand the taper hole can be made small, and the attachment patch can bemade small accordingly, with the less influence on the visual field ofthe wearer. In addition, the taper pin is press-fitted from the frontsurface of the spectacle lens as frequently done. In this case, sincethe nut is not used at the side of the rear surface (concave surface)and not hindered by an extra part on the rear side of the lens, the sideof the rear surface of the spectacle lens can be made simple and clear(concave surface).

A third aspect of the present invention provides the holding structureof the spectacle lens according to either of the first or second aspectof the present invention, in which irregularity means is provided on atlest either of the outer circumferential surface of the taper pin or theinner circumferential surface of the taper hole, so as to increase anengaging force in a slip-off direction of the taper pin when bothsurfaces are press-contacted with each other. Thus, the irregularitymeans is capable of further restricting the slip-off of the taper pin.As the irregularity means, a mat finish surface or a satin finishsurface may be provided on the outer circumferential surface of thetaper pin (fourth aspect of the present invention), or grooves such asannular grooves or spiral grooves may be provided on the outercircumferential surface of the taper pin along the circumferentialdirection (fifth aspect of the present invention). The irregularitymeans can be more easily provided on the side of the taper pin thanprovided on the inner circumferential surface of the taper hole.

In addition, the size of the taper is preferably set to be in a range of1/25 to 1/100 (sixth aspect of the present invention). The above rangeallows the taper pin to be press-fitted into the taper hole withsufficient strength, without damaging the taper hole of the lens.

A seventh aspect of the present invention provides the holding structureof the spectacle lens according to any one of the first to sixth aspectsof the present invention, in which the taper pin has a mark fixedthereon to specify a predetermined press-fitting amount into the taperhole of the spectacle lens.

When press-fitting the taper pin into the taper hole, the taper pin maybe press-fitted while measuring the press-fitting force by a method ofsome kind. However, a special measuring apparatus is accordinglyrequired for measuring the press-fitting force. Therefore, in theseventh aspect of the present invention, the taper pin has a mark fixedthereon to specify a predetermined press-fitting amount. Thus, when thetaper pin has a mark fixed thereon to specify the press-fitting amount,and is press-fitted into the taper hole up to the position as specifiedby the mark, a desired press-fitting force can be generated between thetaper hole and the taper pin. Thus, the taper pin can be press-fittedinto the taper hole easily with a press-fitting amount uniform withoutvariation. Moreover, by setting a press-fitting start position to aspecified distance from the position of the mark, the diameter of thetaper hole to be subjected to machining is accordingly determined. Then,referring to the diameter thus obtained, the machining of the taper holeis preferably conducted.

An eighth aspect of the present invention provides the holding structureof the spectacle lens according to any one of the first to seventhaspects of the present invention in which a rotation preventive means isprovided for the lens holding members and the spectacle lens, therotation preventive means preventing the relative rotation of the taperpin and the taper hole in a state that the taper pin is press-fittedinto the taper hole.

By press-fitting only one taper pin into only one taper hole, there is apossibility that the taper pin starts rotating in the taper hole when anexternal force acts thereon. When starting rotation, the lens isaccordingly rotated, and in addition, the press-contact surface betweenthe taper pin and the taper hole is loosened. Therefore, in an eighthaspect of the present invention, the rotation is prevented by therotation preventive means to prevent the loosened press-contact surfacebetween the taper pin and the taper hole, thus maintaining a reliablepress-contact force.

Various kinds of the rotation preventive means are conceivable. However,in a ninth aspect of the present invention, a rotation preventive pindifferent from the taper pin is provided projecting on the lens holdingmember, and a pin insertion hole different from the taper hole is boredin the spectacle lens. The rotation preventive pin is inserted into thepin insertion hole, to prevent the relative rotation of the taper pinand the taper hole. To put it briefly, by inserting two pins into theholes of the lens, the rotation is prevented. If the two pins areprovided, the taper pin can be used as the rotation preventive pin.However, when press-fitting the two taper pins, higher precision isrequired for the shapes of the taper pins and the taper holes, andintervals between the pins and the holes. Therefore, not a taper pin buta straight pin is more preferable as a rotation preventive pin in termsof an ease of manufacture.

In addition, in a tenth aspect of the present invention, the rotationpreventive pin and the taper pin are parallelly arranged with aspecified distance, and the pin insertion hole and the taper hole areparallelly arranged with a specified distance.

When the two pins are thus parallelly arranged, there are advantagessuch that the design of pin attachment parts of the lens holding membersis simplified to contribute to the ease of machining, and the two pinscan be simultaneously inserted into the holes on the lens side. Notethat the distance between the taper pin and the rotation preventive pin(distance between a root part of the taper pin and the rotationpreventive pin) is preferably set to be 0.5 mm or more, so that thestrength of the lens can be ensured and a reliable rotation preventiveforce can be obtained (eleventh aspect of the present invention).

A position of the rotation preventive pin is not particularly limited tothe lens surface. In a twelfth aspect of the present invention, thetaper pin is press-fitted into the taper hole formed on the lens surfaceof the spectacle lens, and the rotation preventive pin is inserted intothe pin insertion hole formed on the edge surface of the spectacle lens.

When the rotation preventive pin is thus inserted into the edge surfaceof the spectacle lens, only the taper pin may be inserted into the holeformed on the lens surface side. Therefore, the structure and design onthe lens surface side can be simplified.

In a thirteenth aspect of the present invention of a holding structureof a spectacle lens, the rotation preventive pin and the pin insertionhole are arranged with a minute space therebetween. With this structure,machining precision can be intentionally loosened slightly. By filling aresin into the minute space between the rotation preventive pin and thepin insertion hole, the rotation preventive pin is prevented frommoving. The rotation preventive pin is preferably selected to be astraight pin, and the pin insertion hole is preferably selected to be astraight hole in terms of an ease of manufacture and machining.

The rotation preventive means is not limited to a pin. In a fourteenthaspect of the present invention, the rotation preventive means has astructure in which a recessed groove is formed on the spectacle lens,and a part of the lens holding member is fitted into the recessedgroove.

Note that taper pin may be press-fitted into the taper hole under thecondition that an adhesive is injected thereinto. (Fifteenth aspect ofthe present invention).

A sixteenth aspect of the present invention provides a repair method ofa holding structure of a spectacle lens according to any one of thefirst to fifteenth aspects of the present invention, which is a methodfor repairing the loosened relationship between the taper hole and thetaper pin and repairing a damage or modification of the hole,comprising:

-   -   injecting a liquid resin into the taper hole from which the        taper pin is taken out;    -   in this state, the taper pin or the taper pin made for repair        only is inserted halfway into the taper hole to secure a slight        space in a diameter direction between the taper hold and the        taper pin;    -   under such a condition, allowing the liquid resin to be cured;        and    -   after obtaining the cured resin, the taper pin is press-fitted        thereinto, or after taking out the taper pin made for repair        only, the taper pin is press-fitted thereinto.

As described above, when the resin is cured, with the taper pin floated,the taper hole having the taper of the same size as the taper pin andhaving a smaller diameter than the diameter before repairing can beeasily formed. In addition, when the taper pin is press-fitted into thetaper hole after the resin thus injected is cured, the resin functionsas a caulking material. Specifically, not by an adhesive force of theresin, but by the press-fitting force exerted by the press-fitting ofthe taper pin, the lens holding force can be obtained. Thus, theloosened part can be repaired and the main purpose of the presentinvention is achieved.

A seventeenth aspect of the present invention provides spectacles havingthe holding structure of the spectacle lens according to any one of thefirst to fifteenth aspects of the present invention, the holdingstructure being used for a fixed part of endpiece of a spectacle frameand the spectacle lens, or the fixed part of a bridge and the spectaclelens.

An eighteenth aspect of the present invention provides a spectacle framefor which the holding structure of the spectacle lens according to anyone of the first to fifteenth aspects of the present invention is used.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be explained basedon the drawings hereafter.

FIG. 1 is a block diagram showing the whole structure of the spectaclesof a rimless type to which a holding structure of a spectacle lens of anembodiment of the present invention is applied, wherein FIG. 1A is aview of the spectacles viewed from above, and FIG. 1B is a front view ofthe spectacles. FIGS. 2 and 3 are enlarged views showing lens holdingstructure parts in the spectacles. FIG. 2 is different from FIG. 3 inthat FIG. 2 shows a case in which a pin is inserted into the hole on thelens side as a non-through hole, and FIG. 3 shows a case where the pinis inserted into the hole on the lens side as a though hole.

As shown in FIGS. 1 to 3, in spectacles 1, the holding structure of thespectacle lens of the embodiment of the present invention is applied toa fixed part of endpieces 4 of a spectacle frame 2 and spectacle lenses10, and the fixed part of a bridge 5 and the spectacle lenses 10. Theendpieces 4 are attached to each tip of the right and left temples 3 byway of hinges.

In the lens holding structure used for the fixed part of the endpieces 4and the spectacle lenses 10, and the fixed part of the bridge 5 and thespectacle lenses 10, respectively, taper pins 21 formed in tapered shapehaving a thin tip end side are provided projecting on the lens holdingmembers (endpieces 4 and bridge 5), taper holes 11 having tapers ofapproximately the same size as the taper pins 21 are formed on thespectacle lenses 10, and the taper pins 21 are directly press-fittedinto the taper holes 11, and by bringing the inner circumferentialsurfaces of the taper holes 11 into press-contact with the outercircumferential surfaces of the taper pins 21, the spectacle lenses 10are held. In this case, the taper holes 11 are bored in a thicknessdirection of the spectacle lenses 10, and the taper pins 21 arepress-fitted thereinto in the thickness direction of the spectaclelenses 10. Note that in this case, the taper holes are provided from thefront surface in the thickness direction of the lenses, and the taperpins are press-fitted thereinto from the front surface. However, thetaper holes may be provided from the rear surfaces of the lenses in thethickness directions thereof, and the taper pins may be press-fittedthereinto from the rear surfaces of the lenses.

The lenses 10 are made of plastic including a polycarbonate resin, anacrylic resin, a urethane resin, and a polyamide resin, for example. Thesizes of the tapers are set in a range of 1/25 to 1/100.

In addition, in the lens holding members (endpieces 4, bridge 5) and thespectacle lenses 10, rotation preventive means for preventing therelative rotation of the taper pins 21 and the taper holes 11 areprovided, with the taper pins 21 press-fitted into the taper holes 11.In this embodiment, as the rotation preventive means, rotationpreventive pins 22 formed of straight pins, and pin insertion holes 12formed of straight holes are provided. The rotation preventive pins 22and the pin insertion holes 12 are parallelly arranged with specifieddistances. Here, the distances between the pins 21 and the pins 22(distances between the roots of the pins) are respectively set to be 0.5mm or more. Also, the diameters of the rotation preventive pins 22 areset to be 1.0 mm, and the diameters of the pin insertion holes 12 areset to be 1.03 mm, respectively. Thus, with the rotation preventive pins22 inserted into the pin insertion holes 12, slight spaces are formedaround the rotation preventive pins. Therefore, the rotation preventivepins are fixed by filling transparent resins in the spaces thus formed.

As shown in FIG. 2, the taper holes 11 and the pin insertion holes 12may be non-through holes. However, here, as an example, explanation willbe given to a case where through holes are provided as shown in FIG. 3.When the non-through hole is provided, an advantage is that wiping offof sticking dirt on the surface of the lens is eased, if no holes areopened thereon. Meanwhile, when the through hole is provided, anadvantage is that by pushing the tips of the taper pins 21 press-fittedinto the taper holes 11 with a proper jig (tip of a fine pin) from theside opposite to the press-fitting side, the taper pins 21 are easilyunfastened, which is effective for the case where the taper pins 21 needto be unfastened while repairing.

Regarding the arrangement of the taper pins 21 and the rotationpreventive pins 22, as shown in FIG. 2 and FIG. 3, when the taper pins21 and the rotation preventive pins 22 are parallelly arranged, it ispreferable that the taper pins 21 are arranged in the insides of thespectacle lenses 10 (farther side from the edge surfaces of the lenses),and the rotation preventive pins 22 are arranged outsides of the lenses(edge surfaces of the lenses) in terms of securing strength of thelenses. Specifically, if the taper pins 21 are disposed closer to theedges of the lenses, there is a high possibility of damaging the lenseswhile press-fitting. Therefore, the taper holes 21 (center of the holes)is preferably set to the position of about 2 mm or more distant from theedge surfaces of the lenses.

When the lens holding is conducted by combination of the taper holes 11and the taper pins 21, as shown in FIG. 4A, the taper hole 11 is firstlyopened on the spectacle lens 10. The machining of the hole on the lensside is conducted by using a taper reamer having the same taper angle asthat of the taper pin 21. As shown in FIG. 5A, the machining of thetaper hole 11 is conducted so that the straight hole 11 d havingdiameter d1 is firstly opened. Subsequently, as shown in FIG. 5B,machining of the taper hole 11 having diameter d2 is conducted as afinish by the taper reamer from above the straight hole 11 d. Whenopening the taper hole 11 with a diameter of a large diameter at d2=100mm, the lower hole of the straight hole is opened with diameters atd1=0.85 to 0.95 mm, and then by using the taper reamer of 1/50 (tip end0.6 φ, upper end 1.2 φ), the lens is cut until the diameter of the upperhole becomes as thick as 1.0 mm.

After opening the taper hole II on the spectacle lens 10, as shown inFIG. 4B, the taper pin 21 is inserted into the taper hole 11 of the lens10. Even if not applying a load up to a point where the diameter of thetaper pin 21 and the diameter of the taper hole 11 coincide, the taperpin 21 can be inserted. From the point where both diameters coincide,(press-fitting start position), the press-fitting force is applied tothe taper pin 21. Then, as shown in FIG. 4C, while spreading the taperhole 11 of the lens 10, the taper pin 21 is press-fitted thereinto.

At this time, in a case of an elastic lens 10, force F by which the lenstends to shrink works from the inner circumferential surface of thetaper hole 11 to the outer circumferential surface of the taper pin 21.When the force is expressed by taper angle=θ, as a component of theforce F, a force (F cos θ) which is going to push-in the taper pin 21sideward, and a force (F sin θ) which is going to push-back the taperpin 21 work.

For example, when the size of the taper pin is designated as “ 1/50”,the force relations by which the taper pin 21 is press-fitted into thetaper hole 11 are expressed as follows:

-   -   θ=0.573° (taper angle of 1/50)    -   Component of a force which works sideward=F cos θ=0.99995 F    -   Component of a force which works in a pushing back direction=F        sin θ=0.01 F

If a press-contact force which works on a tapered surface is designatedas F=1000 gf, the force (F sin θ) of only 10 gf which is going to pushback the taper pin 21 works, and this is a neglible value. Meanwhile, alateral force (F cos θ) by which the taper pin 21 is prevented fromslipping off is designated as 999.95 gf, and this value shows almost noreduction. At this time, the force by which the taper pin 21 is held isdetermined by a friction coefficient of the taper pin 21 and the lens 10and the force by which the lens is going to shrink. Accordingly, forenhancing a fixing force of the press-contact surface, it is importantto push the taper pin 21 into the taper hole by applying a strongpressure thereto, and roughen the press-contact surface by increasingthe friction coefficient.

The press-fitting force of the taper pin 21 is suitably determined bytaking into consideration the diameters of a pin and a hole, a taperangle, length of the pin, thickness of the lens, distance from the edgeof the hole, and a lens material. For example, by using a lens thin inthickness at a position of the lens hole and therefore considered low instrength, an experiment was conducted under the following condition. Asa result, it was found that when the taper pin was press-fitted into thehole by a press-fitting force of 7 kgf to 10 kgf, the lens was notbroken, and the pin and the lens was connected with a sufficientstrength.

(Experiment Condition)

-   -   Position of the taper hole: The center of the taper hole is 2 mm        distant from the edge of the lens.    -   Thickness at the position of the hole: 1.8 mm    -   Pin: Material (Ti alloy)        -   Taper of 1/50, maximum diameter of 1.1 mm, length (2.5 mm)    -   Lens: Material (Urethane resin; refractive index of 1.6, Product        of HOYA CORPORATION)

As a method for raising the binding force of the press-contact surfacebetween the taper pin 21 and the taper hole 11, it is effective toprovide irregularity means (slip-off preventive means) in a slip-offdirection of the taper pin, on at least either of the outercircumferential surface of the taper pin 21 or the inner circumferentialsurface of the taper hole 11 so as to increase an engagement force. Whenthe elasticity is different between the taper pin and the lens, eitherof which having lower elasticity has preferably the irregularity meansformed thereon. The reason is that a contact area between the taper pinand the taper hole is increased, thereby raising further the bindingforce. For example, in case of a metal taper pin, the taper pin has theirregularity means formed thereon. The irregularity means is generallyformed in such a way that, as shown in FIG. 6A, a roughened frontsurface such as a mat finish surface (formable by means of sandblast andplating) and a satin finish surface is provided on the outercircumferential surface of the taper pin 21, or as shown in FIGS. 6B,6C, and 6D, grooves in the circumferential directions intersecting thepin insertion directions are provided. The kinds of the grooves includejust ring grooves as shown in FIG. 6B, spiral grooves as shown in FIG.6C, and linear grooves as shown in FIG. 6C, and in addition net-likegrooves as shown in FIG. 6D. In FIG. 6D, the net-like grooves arepartially formed around the circumference of the taper pin, and the samenet-like grooves are formed on the rear side thereof also. However, thenet-like grooves also may be formed all around the circumference of thetaper pin.

The grooves as described above may be formed while forming the taperpin, or may be marked later. A laser marking device cab be used formarking.

In case of a plastic lens, the lens is softer and has more elasticitythan a pin. Therefore, if provided with a roughened surface of the taperpin 21, the inner diameter of the taper hole 11 on the lens side ispushed onto the taper pin 21, and the lens is thereby deformed byadapting to the surface shape of the pin and brought into contact withthe pin. Thus, the contact area between the taper pin and the taper holeis increased, thereby increasing the friction coefficient accordingly,to prevent the taper pin 11 from slipping off.

The taper pin 21 may be press-fitted into the taper hole 11 in a statethat an adhesive is injected into the taper hole 11. In this case, whena concavo-convex is formed on the surface of the taper pin 11, theconcavo-convex becomes a storage part of the adhesive, and therefore animprovement in an adhesive force can be expected.

Next, the length of the taper pin 21 (the same is as the rotationpreventive pin 22) will be explained.

The length of the taper pin 21 is preferably set to be a proper lengthcorresponding to a depth of the taper hole 11. The reason is that thelonger the length of the taper pin 21 protruding from the lens is, themore likely that the lens wipe-off is inhibited or the visual field of awearer is disturbed. Meanwhile, the shorter the length of the taper pin21 is, compared with the depth of the taper hole 11, the smaller thecontact area between the taper pin 21 and the inner wall of the taperhole 11 becomes. In this case, the problem is that connection strengthbetween the pin and the lens lowers accordingly.

According to a first method for suitably setting the length of the pin,as shown in FIGS. 7A to 7C, plural kinds of taper pins 21 havingdifferent lengths L1 to L3 are preliminarily prepared. Then, when thethickness of the lens is determined, a taper pin 21 having a most properlength corresponding to the thickness of the lens is selected. Forexample, when there is a taper pin among plural kinds of taper pins,having approximately the same length as the depth of the taper hole ofthe lens, it is preferably selected. When there is no such a taper pin,the taper pin having a length closest to the depth of the taper hole ofthe lens may be selected. In this case, if the taper pin having ashortest protruding length is selected among the taper pins protrudingfrom the lenses, the contact area between the side wall of the taper pinand the inner wall of the taper hole is made large, and therefore theholding strength can be increased, thereby inhibiting the visual fieldof the wearer from being damaged. Moreover, as in the case where thereis no pin having the length longer than the depth of the taper hole ofthe lens, when the taper pin is selected among the pins having thelength shorter than the depth of the taper hole, the taper pin havingthe length closest to the depth of the taper hole is preferablyselected, in terms of contact area which can be made large. In addition,according to a second method for suitably setting the length of the pin,the lens holding member having a longer taper pin 21 is preliminarilyprepared, and when the lens holding member is attached to the lens, thetip of the pin is cut by adapting to the thickness of the lens. In thiscase, it is preferable that one taper pin can deal with a large range ofthickness of the lens.

As described above, by using the taper pin 21 having a proper length, asufficient holding strength of the lens can be secured, without beinghindered by the pin.

Next, directionality of the taper hole 11 will be explained.

As shown in FIG. 8A, the taper hole 11 is preferably bored in aspherical center direction of a base curve of the lens 10. The reason isthat, for example, as shown in FIG. 8B, as an axis of the taper pin 21is shifted from the spherical center direction of the base curve of thelens 10, the area (cross hatching part) brought into full contactbetween the circumference of the taper pin 21 and the inner surface ofthe taper hole 11 in a direction vertical to the insertion direction ofthe taper pin 21 becomes accordingly narrower, thereby lowering theconnection strength of the taper pin and the taper hole.

Also, as shown in FIG. 13A, a corner part of the root of the taper pinis frequently protruded from the side surface of the taper pin. (Such apart is referred to as a fillet part hereafter). The fillet part isformed in a case where a brazing material or the fusion part of a basematerial is swelled out at the time of connecting the taper pin and thelens by brazing and welding, or in a case where the strength is securedby connecting with a smooth curved surface at the time of forming thetaper pin by a press die. Thus, the fillet part is formed in the root ofthe taper pin, and even when press-fitting the taper pin up to the partnear the fillet part, as shown in FIG. 13A, the taper hole 11 ispreferably bored in the spherical center direction of the base curve ofthe lens 10. For example, as shown in FIG. 13B, as the axis of the taperpin 21 is shifted from the spherical center direction of the base curveof the lens 10, the contact area between the taper pin 21 and the innersurface of the taper hole 11 becomes accordingly smaller, therebyraising the possibility that the contact strength is lowered.

Next, a press-fitting method will be explained.

Basic matter in press-fitting the taper pin is to insert it with apredetermined pressure. In the press-fitting method, the taper pin 21may be press-fitted while measuring the pressure when press-fitted.However, here, the shape of the taper pin 21 and the shape of the taperhole 11 are preliminarily set so as to obtain a predeterminedpress-fitting force by inserting the taper pin 21 until it reaches apredetermined position preliminarily set. Thus, a special tool formeasuring the pressure is not required, thereby facilitating the work.

In order to properly set the press-fitting amount, as shown in FIG. 9, amark (such as a line) 21 e for specifying the predeterminedpress-fitting amount into the taper hole 11 of the spectacle lens 10 ispreferably fixed on the outer circumferential surface of the taper pin21. That is, by press-fitting the taper pin 21 into the taper hole 11until the mark 21 e reaches the upper edge of the taper hole 11, thepredetermined press-fitting force is generated. Here, the press-fittingforce (press-fitting height) indicates height dimension S with which thetaper pin is inserted from a contact state between the taper pin 21 andthe inner wall of the taper hole 11 in a non-pressure state(press-fitting start position), and for example, the dimension S ispreferably set to be about 0.5 to 1 mm. Thus, by fixing the mark 21 e onthe taper pin 21, and by press-fitting the taper pin 21 up to theposition of the mark 21 e, a desired press-fitting force can begenerated between the taper hole 11 and the taper pin 21 with an amountuniform without variation, which contributes to a stable lens holdingquality by a comparatively easy work. Note that the mark is not limitedto a line, etc, but may be a groove, a recess or projection, and a step,etc, if the position can be specified by the shape.

FIG. 15 is a view showing an example of fixing a mark 21 e on the outercircumferential surface of the taper pin 21 for specifying the specifiedpress-fitting amount, and fixing a mark 21 f on the tip side of the pinfor specifying the press-fitting start position. The mark is notparticularly limited in the same way as the mark 21 e specifying thepredetermined press-fitting amount. However, in the example of FIG. 15,the mark is formed of a groove. When the taper pin is press-fitted intothe taper hole by specifying the press-fitting start position 21 f by arecessed part such as a groove and injecting an adhesive, the markshowing the press-fitting start position preferably serves as a storagepart of the adhesive after press-fitting. Here, the press-fitting startposition corresponds to a height position up to which the taper pin 21gets into the taper hole in a non-pressure state, and usually thediameters are matched between the diameter of the taper pin 21 and thediameter of the taper hole 11. Then, heights of the mark showing thepress-fitting start position and the mark showing the predeterminedpress-fitting amount are set in advance, so that the predeterminedpressure is generated. In this case, as shown in FIG. 15A, the taperhole 11 is machined so that the press-fitting start position 21 f of thetaper pin 21 is positioned on the upper edge of the taper hole 11. Then,as shown in FIG. 15B, the taper pin 21 is press-fitted into the taperhole 11 until the mark showing the predetermined press-fitting amountreaches the upper edge of the taper hole 11. In this case, the machiningamount of the taper hole can be determined by referring to the mark 21 fof the press-fitting start position, thereby facilitating the machiningof the taper hole 11.

In the holding structure of the spectacle lens having theabove-described structure, the lens holding force is obtained by thedirect press-contact between the outer circumferential surface of thetaper pin 21 and the inner circumferential surface of the taper hole 11(without using a bush). Therefore, the lens is surely held withoutshaking and unfastening. Moreover, the number of fine parts (such as abush and a slip-off preventive pin) can be reduced, thereby simplifyingthe structure, and also simplifying the design.

Further, without using the bush and a cylindrical pin, only the thintaper pin 21 and the rotation preventive pin 22 are used, thereby makingthe diameters of the holes 11 and 12 on the spectacle lens 10 side smallto prevent lowering of the strength of the lens. Particularly, by makingthe diameter of the pin small, a pin attachment patch on the lensholding member side (endpieces 4 and bridge 5) can also be made small,to enable easing restriction in design. Moreover, in addition to thesimple structure, the hole formed on the lens 10 can be made small.Therefore, the holding structure of the spectacle lens having theabove-described structure can be applied to a thin lens withoutdeveloping so much trouble.

In addition, in the holding structure of the spectacle lens of theabove-described embodiments, the taper pin 21 and the rotationpreventive pin 22 are inserted in the thickness direction of the lens,and therefore the attachment patch to which the above-described pins areattached is easy to come into the visual field of the user. However, asdescribed above, by the smaller specified diameter of the pin, theattachment patch can also be made small, and the taper hole 11 can bemade closer to the edge of the lens, resulting in less influence on thevisual field of the wearer. Also, without using a nut, the rear side ofthe lens can be simple and clear not hindered by an extra part.

Moreover, in the holding structure of the spectacle lens of theabove-described structure, a rotation preventive pin 22 is arranged inparallel to the insertion direction of the taper pin 21, thereby easilysimplifying the design of the pin attachment part of the lens holdingmembers (endpieces 4 and bridge 5), and facilitating the machining. Inaddition, two taper pins 21 and 22 can be simultaneously inserted intothe taper holes 11 and 12, and the rotation preventive pin 22 and thepin insertion hole 12 are capable of functioning to guide the insertiondirection of the taper pin, thereby improving the easiness in assemblingwork also. In addition, by more largely opening the pin insertion hole12 than the size of the rotation preventive pin 22, a machiningprecision for setting the distance between the pins 21 and 22, and thedistance between the holes 11 and 12 can be intentionally loosenedslightly.

In addition, the slight space between the rotation preventive pin andthe pin insertion hole is fixed by filling a resin therein. In a fillingmethod of the resin, for example, the resin may be preliminarily filledin the pin insertion hole 12 before the rotation preventive pin isinserted, or after insertion, the space between the rotation preventivepin and the pin insertion hole may be filled. The kinds of the resinthat can be used include, for example, an epoxy resin, an acrylic resin,a urethane resin, and a rubber resin. A transparent resin is morepreferable, and the resin having a refractive index close to therefractive index of the lens is further preferable.

In the embodiments described above, a straight pin is selected as therotation preventive pin 22, and a straight hole is selected as the pininsertion hole 12, and therefore the above-described effect can furtherpreferably be obtained with a simple structure.

Also, when the spectacle having the above-described structure issubjected to a temperature test, the slip-off of the pin did not occur.The condition of the temperature test is as follows:

-   -   (1) After left to stand in an environment at 50° for 30 minutes,        the spectacles are left to stand at −20° for 30 minutes.    -   (2) 20 cycles of this is repeated.    -   (3) Thereafter, the environment is back to a room temperature,        and a pin pull-off load of 1 kgf is applied.

Next, the pin rotation preventive structure other than theabove-described structure will be explained.

As described before, two or more pins are previously prepared and it iseffective that at least one of them is selected to be a taper pin 21. Inthis case, as shown in FIG. 10A, the two pins 21 and 22 can be laterallyarranged as shown in FIG. 10A, the two pins can be vertically arrangedas shown in FIG. 10B, or the two pins can be obliquely arranged alsowithout difficulty functionally, and whichever of them can be freelyselected as design requires.

Moreover, for example, the position to form the rotation preventive pin22 is not particularly limited to the surface of the lens. As shown inFIG. 11, the rotation preventive pin 22 may be inserted into the edgesurface 10 a of the spectacle lens 10, with the taper pin 21press-fitted into the surface of the lens of the spectacle lens. Thus,if one pin 22 is arranged on the edge surface 10 b side, easy layout isprovided for the taper pin 21 on the lens surface side. Moreover, inpress-fitting, an adhesive is preliminarily applied or filled in theinsertion hole of the rotation preventive pin, and in this state, therotation preventive pin may be inserted into the pin insertion holesimultaneously with the press-fitting of the taper pin, and the rotationpreventive pin and the inner wall of the insertion hole are therebybonded with each other. With this structure, the taper pin can moresurely be fixed.

In addition, the rotation of the taper pin can be prevented withoutusing the pin. As shown in FIG. 12, in one of the rotation preventivemeans, a recessed groove 15 is formed on the spectacle lens 10, and apart of the lens holding member (endpiece 4) is fitted into the recessedgroove 15 on the lens side by using one pin in this case.

In FIG. 14, in another example of the rotation preventive means, therecessed groove is formed on the edge of the spectacle lens 10 along theinsertion direction of the taper pin, and a part of the lens holdingmember (endpiece 4) is fitted thereinto by using one pin in this casealso.

Next, a repair method for repairing the above-described holdingstructure of the lens, when the relation between the taper hole 11 andthe taper pin 21 is loosened will be explained.

The above repair method comprises:

-   -   injecting a liquid resin (adhesive) into the taper hole 11 from        which the taper pin 21 is taken out;    -   in this state, inserting the taper pin 21 halfway into the taper        hole 11 to secure a slight space in a direction of the diameter        between the taper hole 11 and the taper pin 21;    -   under this condition, allowing the resin to be cured; and    -   after obtaining the cured resin, press-fitting the taper pin 21.

For example, the halfway insertion of the taper pin 21 is conducted insuch a way that in a case of the taper pin 21 of 1/50, the taper pin 21of about 1 mm is pulled out from the taper hole 11 to form a slightspace of about 0.02 mm in a direction of the diameter. Under thiscondition, the resin is cured. The kinds of the resin that can be usedinclude, for example, an epoxy resin, an acrylic resin, a urethaneresin, and a rubber resin. Note that the transparent resin ispreferable, the transparent resin is more preferable, and the resinhaving a refractive index close to the refractive index of the lens isfurther preferable.

As described above, when the resin is cured with the taper pin floated,the taper hole having a taper of the same size as the taper pin andhaving a smaller diameter than the diameter before repairing can beeasily formed. In addition, when the taper pin 21 is press-fitted intothe taper hole 11 after the resin thus injected is cured, the resinfunctions as a caulking material. Specifically, not by an adhesive forceof the resin, but by the press-fitting force exerted by thepress-fitting the taper pin, the lens holding force can be obtained.Thus, the loosened part can surely be repaired. Here, the taper pin ofthe holding part was used for repair. However, a taper pin of exclusiveuse for repair, which is a tool of exclusive use for repair having thesame taper, can also be used. In this case, it is necessary to removethe tool after the resin is cured, and therefore a taper part ispreferably weak in adhesive strength with the adhesive. For example, thetaper pin is preferably made of metal, glass, and rubber, etc,. Inaddition, the taper pin may also be made of the resin having smallfriction coefficient such as a fluorocarbon resin or the material coatedby the same.

Moreover, regarding the method for press-fitting the taper pin, in theabove-described embodiments, the taper pin 21 was press-fitted into thetaper hole 11 in an environment of a room temperature. However, thetaper pin 21 may also be fitted into the taper hole in a preliminarilyheated state of the spectacle lens. In this case, by the shrinkage ofthe lens when it returns to a room temperature, the taper pin 21 canfurther securely be fixed.

In addition, in the above-described embodiments, although rotation isprevented by the means (such as a rotation preventive pin 22) differentfrom the taper pin 21, it also is possible to form the section of thetaper pin into a non-rotational shape such as an elliptic shape or apolygonal shape, so that the taper pin itself has a function to preventthe rotation.

Also, in the above-described embodiments, although the taper pin 21 ispress-fitted into the surface of the lens of the spectacle lens 10, itis also possible to constitute the holding structure of the spectaclelens so that the taper pin 21 is press-fitted into the edge surfaces 10a and 10 b of the spectacle lens 10.

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, without usingscrewing members such as a screw and a nut, and extra parts such as abush, a cylindrical pin, and a slip-off preventive pin, with a simplestructure, the spectacle lens can surely be held without shaking.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the whole structure of spectacles towhich a holding structure of a spectacle lens of an embodiment of thepresent invention is applied, and FIG. 1A is a view showing thespectacles viewed from above, and FIG. 1B is a front view of thespectacles.

FIG. 2 is an enlarged view showing a first example of a lens holdingstructure part in the spectacles of FIG. 1.

FIG. 3 is an enlarged view of a second example of the lens holdingstructure part in the spectacles of FIG. 1.

FIG. 4 are views showing a relationship between taper pins and taperholes in the holding structure of the spectacle lenses, FIG. 4A is aview showing a state before press-fitting the taper pin into the taperhole, FIG. 4B is a view showing a state after press-fitting the taperpin into the taper hole, and FIG. 4C is a view showing a forcerelationship in a state after press-fitting the taper pin.

FIG. 5 are explanatory views of a process in which the taper holes areformed, FIG. 5A is a sectional view showing a stage in which a lowerhole is made, and FIG. 5B is a sectional view showing a stage in whichthe lower hole is finished into a taper hole.

FIG. 6A to FIG. 6D are views showing irregularity means formedrespectively on the surfaces of the taper pins.

FIG. 7A to FIG. 7C are views showing the taper pins made different inlengths.

FIG. 8 are explanatory views concerning the orientations of the taperpins, wherein FIG. 8A is a sectional view showing an example ofpress-fitting the pin in a spherical center direction of a lens, andFIG. 8B is a sectional view showing an example of press-fitting the pinin a direction shifted from the spherical center direction of the lens.

FIG. 9 are explanatory views of a press-fitting method of the taperpins, wherein FIG. 9A is a sectional view of the state beforepress-fitting the taper pin, and FIG. 9B is a sectional view showing thestate at the time of completing the press-fitting of the taper pin.

FIG. 10 are explanatory views of rotation preventive means in theholding structure of the spectacle lens, wherein FIG. 10A is a viewshowing an example of laterally arranging two pins, and FIG. 10B is aview showing an example of vertically arranging the two pins.

FIG. 11 are views showing other examples of the rotation preventivemeans, wherein FIG. 11A is a perspective view, and FIG. 11B is a frontview.

FIG. 12 is a perspective view showing further other example of therotation preventive means.

FIG. 13 are other explanatory views of the orientations of the taperpins, wherein FIG. 13A is a view showing an example of press-fitting thepin in the spherical center direction of a lens, and FIG. 13B is asectional view showing an example of press-fitting the pin in adirection shifted from the spherical center direction of the lens.

FIG. 14 is a perspective view showing further other example of therotation preventive means.

FIG. 15 are other explanatory views of the press-fitting method of thetaper pins, wherein FIG. 15A is a sectional view showing a state beforepress-fitting the taper pin, and FIG. 15B is a sectional view showing astate of completing the press-fitting of the taper pin.

DESCRIPTION OF THE SIGNS AND NUMERALS

-   1 SPECTACLES-   4 ENDPIECE (LENS HOLDING MEMBER)-   5 BRIDGE (LENS HOLDING MEMBER)-   10 SPECTACLE LENS-   10A, 10B EDGE SURFACE-   11 TAPER HOLE-   12 PIN INSERTION HOLE-   15 RECESSED GROOVE-   21 TAPER PIN-   22 ROTATION PREVENTIVE PIN

1. A manufacturing method of a spectacle, which is a manufacturingmethod of a rimless spectacle for holding a spectacle lens by a lensholding member of a spectacle frame, wherein a taper pin is providedprojecting on the lens holding member, said manufacturing methodcomprising the steps of: boring a taper hole having approximately thesame taper size as the taper pin, on or through the spectacle lens; anddirectly press-fitting the taper pin into the taper hole, so as to holdthe spectacle lens by a press-contact between an inner circumferentialsurface of the taper hole and an outer circumferential surface of thetaper pin.
 2. The manufacturing method of the spectacle according toclaim 1, wherein the taper hole is bored in a centripetal direction of abase curve of the spectacle lens.
 3. The manufacturing method of thespectacle according to claim 1, wherein the taper pin is press-fittedinto the taper hole by inserting it into the taper hole at apredetermined pressure.
 4. The manufacturing method of the spectacleaccording to claim 1, wherein the taper pin is press-fitted into thetaper hole by inserting the taper pin up to a predetermined position. 5.The manufacturing method of the spectacle according to claim 1, whereinthe taper pin is press-fitted into the taper hole in a state that thespectacle lens is previously heated in the step of press-fitting thetaper pin into the taper hole.
 6. The manufacturing method of thespectacle according to claim 1, wherein the lens holding member isselected in accordance with a depth of the taper hole, from a pluralityof members having different lengths of the taper pin.
 7. Themanufacturing method of the spectacle according to claim 1, whereinafter the taper pin is press-fitted into the taper hole, a tip end ofthe taper pin is cut.
 8. The manufacturing method of the spectacleaccording to claim 1, wherein an irregularity part is provided on thetaper pin.
 9. The manufacturing method of the spectacle according toclaim 1, wherein a rotation preventive means composed of a straight pinparallel to the taper pin is provided in the lens holding member, and apin insertion hole composed of a straight hole parallel to the taperhole is provided in the spectacle lens, and when the taper pin ispress-fitted into the taper hole, the rotation preventive pin isinserted into the pin insertion hole.
 10. The manufacturing method ofthe spectacle according to claim 9, wherein after the rotationpreventive pin is inserted into the insertion hole, a space between therotation preventive pin and the pin insertion hole is filled with resin.11. The manufacturing method of the spectacle according to claim 9,wherein after resin is injected into the pin insertion hole, therotation preventive pin is inserted into the pin insertion hole.
 12. Themanufacturing method of the spectacle according to claim 9, wherein adiameter of the pin insertion hole is larger than an outer shape of therotation preventive pin.
 13. The manufacturing method of the spectacleaccording to claim 9, wherein the rotation preventive pin is arrangedoutside the spectacle lens to the ear side from the taper pin.